Join or Union or Subquery or something else? - sql

Question

I have two tables which I need to join/union for a distinct set - but every query I've tried so far results in too few/too many rows returned.
table one table two
ID Type
Type SubType
SubType
Percentage
Category
Table one is the main data set, table two is lookup values.
The data is something like this:
table one
1, A, ZZZ, 20.00, CAR
2, A, YYY, 80.00, CAR
3, B, YYY, 100.00, VAN
4, A, WWW, 100.00, BUS
table two
A, WWW
A, XXX
A, YYY
A, ZZZ
B, YYY
B, ZZZ
What I'm looking to end up with is the following data set
1, A, YYY, 80.00, CAR
2, A, ZZZ, 20.00, CAR
0, A, WWW, 0.00, CAR
0, A, XXX, 0.00, CAR
3, B, YYY, 100.00, VAN
0, B, ZZZ, 0.00, VAN
4, A, WWW, 100.00, BUS
0, A, XXX, 0.00, BUS
0, A, YYY, 0.00, BUS
0, A, ZZZ, 0.00, BUS
So, in other words I want all the data from table one PLUS any missing SubTypes from table two that match the Type of table one which would also include zero values for ID and Percentage, but keep the Category from the data set selected.
This works fine with an outer join if I only have one row in table one, but for each subsequent row my query adds more rows from table two. I think I need some sort of union or subquery that is aware of other rows selected from table one so will only select non-matching rows from table two.
Any help most appreciated!
Edit:
This is my current query (the more I think about this the more wrong it looks)
SELECT CASE WHEN t1.SubType = t2.SubType THEN t1.ID ELSE 0 END,
t1.Type, t2.SubType, CASE WHEN t1.SubType = t2.SubType THEN
t1.Percentage ELSE 0 END, t1.Category
FROM one t1
LEFT OUTER JOIN two t2
ON t2.Type = t1.Type
This gives me 8 rows - duplicated for each row selected from table one.
Another Edit:
Adding a couple more rows to table one I think explains this problem better. So the SQL to create tables and add rows looks like this:
create table one (ID int,Type nvarchar(1),SubType nvarchar(3),Percentage decimal(5,2),Category nvarchar(3))
create table two (Type nvarchar(1),SubType nvarchar(3))
insert into one values (1, 'A', 'ZZZ', 20.00, 'CAR')
insert into one values (2, 'A', 'YYY', 80.00, 'CAR')
insert into one values (3, 'B', 'YYY', 100.00, 'VAN')
insert into one values (4, 'A', 'WWW', 100.00, 'BUS')
insert into two values ('A', 'WWW')
insert into two values ('A', 'XXX')
insert into two values ('A', 'YYY')
insert into two values ('A', 'ZZZ')
insert into two values ('B', 'YYY')
insert into two values ('B', 'ZZZ')

Answer 1

I think this will do what you want:
SELECT ID, Type, SubType, Percentage, Category
FROM Table1
UNION ALL
SELECT 0, Type, SubType, 0.00, 'CAR'
FROM Table2 t2
LEFT JOIN t1 ON t1.Type = t2.Type AND t1.SubType = t2.SubType
WHERE t1.ID IS NULL

Answer 2

SELECT
ISNULL(t1.ID),
t2.Type,
t2.SubType,
ISNULL(t1.Percentage, 0),
ISNULL(t1.Category, 'CAR')
FROM Table2 t2
INNER JOIN (SELECT DISTINCT Type FROM Table1) f ON t2.Type = f.Type
LEFT JOIN Table1 t1 ON t2.Type = t1.Type AND t2.SubType = t1.SubType

Answer 3

You can do this without a UNION, just a LEFT JOIN:
UPDATED FOLLOWING COMMENT
SELECT ISNULL(t1.ID,0) Id, t2.Type, t2.SubType, ISNULL(t1.percentage,0) Percentage, ISNULL(t1.Category,'CAR') Category
FROM Table2 t2
LEFT JOIN Table1 t1
ON t1.Type = t2.Type AND t1.SubType = t2.SubType
WHERE t2.Type IN (SELECT DISTINCT Type FROM Table1)
Ok, this will give you the result you want, but its assigning the category as 'CAR', if you don't want that, then you should tell us what it should be.

Answer 4

Thanks for everyone's help on this, but I've worked it out myself finally...
SELECT ID, Type, SubType, Percentage, Category
FROM one
UNION
SELECT DISTINCT 0, t2.Type, t2.SubType, 0.00, t1.Category
FROM one t1
INNER JOIN two t2 ON t2.Type = t1.Type AND t2.SubType NOT IN
(SELECT t3.SubType FROM one t3 WHERE t3.Category = t1.Category and t3.Type = t1.Type)
ORDER BY Category, Type, SubType